Fig. 2.

CO₂ added as such supports the peroxidation activity of SOD1. Reaction conditions shown are essentially as in Fig. 1, except that water at 0°C saturated with CO₂ gas was the last component added in place of . Line 1, CO₂ added at the arrow to reaction mixture as in Fig. 1; line 2, CO₂ added at the arrow to a reaction mixture as in Fig. 1 but containing 0.2 mg/ml SOD1; line 3, as in line 2 but with 0.1 mg/ml carbonic anhydrase in the reaction mixture.